1. Field of Invention
This invention pertains generally to semiconductor memory devices and, more particularly, to a semiconductor memory and method of storing configuration data for the memory.
2. Related Art
Configuration data for semiconductor memory devices is typically stored in fuses or other volatile or non-volatile devices, e.g. registers, which are outside the main memory array. Such data is generated during the testing of the devices and may, for example, include wafer information, wafer sorting information, failed addresses, option control information, and other information which is utilized during start-up of the devices.
In order to increase manufacturing yields, many semiconductor memory devices include redundant areas or cells which can be used to replace defective portions of the array. This technique is sometimes referred to as redundancy repair, and in memory devices utilizing it, the redundancy repair information is included in the configuration data. The repair information is stored after all repairs have been made, and when reading information from the memory, the repair information needs to be ready before the actual array read. If the configuration data were stored in the main memory array, there is a chance that it could be written into a repaired area, and that it could not be read out correctly because the repair information which needs to be known in order to read it would not be available yet.